McLin, I found this by typing in 1990 Thunderbird body kit in Google:
http://www.bizrate.com/automotiveper...__nwylf--.html
You could also try Ebay but I think shipping will be quite expensive to Germany so check speed shops near you. I don't have a wiring diagram for your year Bird so I can't help you with your digital dash question. Maybe someone else can help you.